Rule 812 This article is not intended to alter or change the existing substantive law, whether statutory or decisional, interpreting the meaning of “market val…

This rule is basically a "nothing changes" rule. It says that the laws and court decisions that already explain what "market value" means still apply. The article did not create any new definitions or change how courts figure out what something is worth.

If you are in a case where property value matters, like an eminent domain case, judges and lawyers will still use the same standards they always have. This rule just makes clear that the existing rules about market value were not accidentally changed or replaced.